Hello there.
I am a PHP programmer and I think I can help you create an online system to you for inputting client data. To store the data, you may need a database server and I can provide this service to you. It would be easy to use.
Although I am new as a freelancer, I have created and have maintained a CMS for my previous company and I am sure that I can handle this for you. Please feel free to contact me if you want to hire me, so that we can discuss further with your project.